Content area
Full text
The human-computer interface (HCI)-the point at which a human and computer (or other intelligent device) meet-can be rife with misunderstandings. Computer jargon, even when written in English, can seem to be a foreign language. A human user, on typing a query, may not understand the computer response "error 404," which loosely translated means "I cannot find what you are looking for."
HCI is also described and strongly influenced by the manner in which human-computer interactions occur. For the human, the computer predominately communicates through its display and use of colors, size, and location of fonts, icons, waveforms, images, audible responses/ alarms, synthesized speech, or through tactile stimulation.
For the computer, a key stroke, mouse click, screen tap, or voice command from the human may suffice. Increasingly, natural user interfaces (NUIs) that respond to human gestures and speech may eventually replace the currently standard graphical user interface (GUI),1 which revolutionized human-computer usability by allowing a user to interact with the computer via images such as pointers, icons, and folders, instead of command line text.
When these interaction techniques are mismatched or break down, mistakes are made, user frustration increases, and faith in the system declines. A software designer's job is to prevent or minimize such a breakdown and optimize the human-computer relationship. It requires at the very minimum some understanding of the concepts associated with human perception and cognition.
It is essential to take visual, auditory, and tactile communication aspects into account early in the design process, in order to produce a safe and usable medical device or software system. The focus of this paper is limited to the visual and cognitive factors that strongly influence user performance and satisfaction at the level of not only the HCI, but the human-medical device interface as well.
Classic Human Factors Model Of the Human-Machine System
Human factors engineering (HFE), a highly interdisciplinary and systems science, has contributed greatly to our understanding of how humans not only interact with machines in general but with computers and embedded devices in particular. These contributions have come largely through empirical research, models, and accident investigations, especially where a disregard for the human user was found to be a contributing cause of the accident.
A classic model that can be applied directly to...